again and put fresh Aqua fortis upon it, set it again with the Vessel over the fire, and let it work: this is done, because if the first Aqua fort. were grown too weak, and had lost somewhat of Silver by the Rolls, that the other Aqua fort. might touch it again, and make it clean. Take notice also, That you may cause the last Aqua fort. to work in great Bubbles, that the Roles may become very clean, and put in the second Aqua fort. which hath not beenused, for it hath its strength as before.
[Section. 8] Then put clean sweet warm water upon the little Rolls, (Rain Water is the best for it) let it stand a little, and put more warm, or rain Water, upon it again, and set the Glasses with the Rolls over a coal fire, let it boil and work in great Bubbles, then take it off, and casting the water again away, this do three times with warm or rain water, that the silvery Aqua fort. which did hang about the little Rolls be dulcified, then is it enough: When the little Rolls are thus clean and sweet, then put them out very gently, with the last sweet water in a glaz'd pot or glass bottle, and pour the water off from it, and take the Golden Rolls with clean Pincers out of the Pot, and put them in a clean cloth to suck the rest of the water into it, and the Rolls will look very fine and brown.
[ 9] Then put them into the Golden pott, and after, put them into an Assay-Oven, but not in an exstream heat∣ing, and glow them well and they will become as fine as a pure Gold: When this is done, Take the two little Rolls, weigh them one against the other, and if they are alike in weight, then have you proved them right: next, put them together in a weigh-scale, and weigh them with the Carat-weight, and how much they do weigh, so much containeth the Mark (of the mixt Gold) in fine Gold: this only is to be observed, That the weight of the Wa∣ter,